"I've been saddened to witness friends being labelled or attacked for respectfully questioning and examining certain topics. Topics that are not only relevant to the potential health and safety of their own families, but to everyone on the planet."

"If over 4,000 peer reviewed reports describe injuries from wireless and thousands of EMF scientists and medical doctors (and ex-Telco employees) around the world are reporting harmful biological effects from wireless radiation — these would be rational questions, wouldn't they?"

Lucas proceeded to reference brain surgeon Dr Charlie Teo, who has previously drawn a connection between tumours and electromagnetic frequencies.

Isabel Lucas arrives ahead of the Australian premiere of 'That's Not Me' during the Sydney Film Festival at State Theatre on June 10, 2017 in Sydney, Australia. (Getty)

"If you don't personally believe 5G is harmful, that's okay but may I gently ask, what could be lost if we all paused for a moments re-evaluation? If there is a possibility that a re-evaluation could benefit our global health and humanity, is it not worth it?

"We are aware of the issues and as of today, Ms Lucas and Plan International have come to a mutual agreement to end the ambassadorship," the organisation's wrote to their official Twitter account on April 15.